The present invention relates generally to devices which reduce the risk of infection associated with the use of disposable medical implements in hospitals and other medical facilities (such as a clinic or doctor's office), and, more particularly, to hypodermic needle/syringe devices used in blood collection and medicinal injection procedures, wherein the needle and syringe are pre-assembled in a device housing adapted to fixedly project the needle therefrom to perform the procedure, and, after the procedure is performed, safely retract the needle back into the housing for disposal, substantially without risk of contaminating contact by the operator of the device with the used needle or syringe.
In today's hospitals, a wide variety of disposable needle and syringe devices are routinely used to administer medication by injection, for intravenous blood collection, and for insertion of catheter devices. For the typical injection procedure, the nurse or medical technician will assemble a sterile needle/syringe device and pre-fill the syringe with medication at the nurses' station or at a medication cart outside the patient's room. During blood collection procedures, the nurse will assemble a sterile needle/syringe device to draw blood for immediate transfer to a vacuum tube collection device, or draw the blood directly into the collector by means of a multi-sample needle/collection tube holder device.
For catheter insertion procedures, the catheter tube is slipped over a hypodermic needle which is then grasped by its hub portion to guide the catheter into the patient's vein. Often, while the needle and catheter are held in place, a syringe is affixed to the needle hub and then operated to draw a small potion of blood from the vein to ensure that the catheter has been properly placed. Thereafter, the catheter is held in place and the needle is removed from the vein. The catheter will then be typically hooked up via a tubing connection to an intravenous ("I.V.") apparatus. A potential danger inherent in such a procedure results from the fact that once the needle guiding the catheter punctures the patient's vein, blood will shoot out through the needle and possibly onto the clothes or skin of the person performing the catheterization.
With the widespread use of disposable hypodermic needles and syringes, there exists a definite need for ways to safely and conveniently dispose of such implements after use without risk of exposing medical personal handling them to injury, infection or disease by puncture or contact with a used needle or syringe. Today's health professionals, especially those who attend to patients suffering from highly contagious diseases such as Acquired Immune Deficiency Syndrome ("AIDS") and Hepatitis, are acutely aware of such risks.
Once a needle and/or syringe is used, both implements are contaminated and must be disposed of in a safe manner. It had been once common practice to break or cut the needle after use before transport to ultimate disposal in order to eliminate the sharp end point and thereby reduce the risk of puncture, scratching or other injury which might result from handling. Such practices are now disfavored because of the substantial danger of an accidental puncture during the breaking or cutting operations, and the recognition that the cutting tool itself can be a breeding ground for disease-causing micro-organisms.
While the used needle presents the most significant risk of injury or infection through accidental puncture or scratching of a person's skin, the used syringe may also present a risk of infection. For example, a used syringe can contain residual blood or medication which, if exposed to a person's skin, may be absorbed topically (particularly if a cut or break is present) and may cause a serious internal infection or other reaction.
As a result of the foregoing dangers, it is preferred current practice to dispose of such devices in-tact, without dismantling them. In disposing of the whole hypodermic needle and syringe, however, medical personnel would sometimes attempt to recap the used needle before disposal with the same protective cap that covered the needle during shipment from the manufacturer. This practice itself could result in accidental puncture or contact while the needle point is being recapped. Because of this danger, it is now recommended by the Center For Disease Control ("C.D.C") that needles not be recapped after use.
In order to overcome such difficulties, various retractable needle/syringe devices have been developed wherein a hypodermic needle is pre-assembled within a syringe or device housing adapted to dispense a volume of injectant, and which provides means for fixedly projecting the needle from the device to give an injection and retracting it back into the device for disposal. For example, U.S. Pat. No. 4,507,117 to Vining et al. describes a needle/syringe device wherein the needle is fixedly projected from the syringe by lockingly engaging a pair of locking members formed on the syringe plunger with a pair of recessed portions formed on the needle mounting base, and then lockingly engaging a second pair of locking members formed on the mounting base with a second pair of recessed portions formed on the neck of the syringe barrel. The plunger must be rotated clockwise to lock each pair of locking members to their respective recessed portions. To fill the syringe with medication, the plunger is unlocked from the mounting base and drawn back as in a conventional syringe. The needle is retracted after injection by unlocking the base from the neck and drawing back on the plunger.
U.S. Pat. No. 4,767,413 to Haber et al. discloses a dental syringe wherein a pre-filled ampule of medication is spring biased within a cylinder proximate a hypodermic needle. A retaining collar engaging the ampule is pushed into the cylinder to place the ampule into fluid communication with the needle and project the needle from the cylinder against the yielding spring. To keep the needle in a projected state, the operator of the device uses two fingers to compress a pair of opposed spring-like locking arms formed on the cylinder into engagement with a locking skirt formed on the retaining collar. Holding the locking arms in this position, the operator then uses his thumb to depress a plunger member into the ampule to discharge the injectant therefrom. To retract the needle, the operator releases the locking arms causing the spring to urge the ampule and needle back to their pre-injection positions.
The art also discloses retractable needle mechanisms for use in catheter insertion procedures. For example, U.S. Pat. No. 4,747,831 to Kulli discloses a needle/handle assembly wherein the needle lockingly projects outwardly from a bore formed in the handle. When the catheter has been placed, a spring activated retraction mechanism provided for the handle can be operated to automatically retract the needle into the handle.
While the foregoing devices should generally yield good results, they suffer some disadvantages. First, the Vining et al. and Haber et al. devices can be cumbersome to operate. The Vining et al. device requires multiple steps to lockingly project the needle from the syringe, requires unlocking of the plunger from the needle mounting base to draw fluid into the syringe, and requires unlocking of the base from the syringe neck to retract the needle. The Haber et al. device requires the operator to rely on finger pressure exerted by two fingers on the locking arms to hold the needle in a projected state while attempting to give the injection using a third finger of the same hand.
These injection devices suffer a further drawback where the site of the injection is critical. For example, drugs such as xylocaine and novocaine, if administered intravenously, can cause a patient to have a cardiac arhythmia which can subsequently result in death. Accordingly, these drugs must be administered intramuscularly or in fatty tissue. When a conventional needle/syringe device is used to give the injection, the syringe plunger is drawn back slightly prior to injection to "aspirate" for blood and thereby ensure that the needle has not been inadvertently placed in a patient's vein or artery. If blood appears in the injectant through the aspiration process, a new site for the injection must be chosen. Moreover, because of the potential contamination to the injectant by the blood, the injectant should be replaced. The Haber et al. device is adapted to dispense an ampule of medication and provides no means to aspirate for blood. The Vining et al. device can only aspirate for blood like a conventional syringe, and thus, cannot protect the injectant from contamination.
In the Kulli catheter insertion device discussed above, the needle is constantly in a projected state outside of the handle prior to use. As a result, there exists a greater risk of potential contamination to the needle from dropping or otherwise mishandling the device, and thus, a greater risk to persons operating the device of coming into contaminating contact with the needle.
Accordingly, it is an object of the present invention to provide new retractable needle/syringe devices which overcome the foregoing disadvantages of the prior art. It is also an object of the present invention to provide new retractable needle/syringe devices for use in blood collection, medicinal injection and catheterization procedures, which can be economically fabricated, and which are of a durable yet lightweight construction.
It is another object of the present invention to provide new retractable needle/syringe devices which are compact in size so as to be easily placed in a uniform pocket prior to use, and easily locked inside a standard hospital medication cart when unattended, thus obviating the risks caused by leaving unattended devices in a patient's room.
It is a another object of the present invention to provide new retractable needle/syringe devices wherein the entire device can be safely transported to ultimate disposal after use without need to remove the needle from the syringe, thus substantially reducing the risk of exposing the person handling the device to injury, infection, or disease by puncture or contact with the used needle or syringe.
It is yet another object of the present invention to provide new retractable needle/syringe devices for use in blood collection, medicinal injection, and catheterization procedures, wherein the needle and syringe are pre-assembled in a device housing adapted to automatically lockingly project the needle therefrom by use of a simple push button mechanism, leaving the hands of the person using the device free to operate the syringe, and safely retract the needle back into the housing after use by means of the same push button.
It is still another object of the invention to provide a retractable needle/syringe device capable of dispensing a pre-filled ampule of medicament, wherein the device can be operated to aspirate for blood prior to giving the injection, when necessary, substantially without danger of contamination to the medicament.
The foregoing specific objects and advantages of the invention are illustrative of those which can be achieved by the present invention and are not intended to be exhaustive or limiting of the possible advantages which can be realized. Thus, these and other objects and advantages of the invention will be apparent from the description herein or can be learned from practicing the invention, both as embodied herein or as modified in view of any variations which may be apparent to those skilled in the art. Accordingly, the present invention resides in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.